Electrochemical characteristics of (PEM) electrolyzer under influence of charge transfer coefficient.

In this paper a systematic understanding of how charge transfer coefficient (CTC) and exchange current density contributes to polarization and performance characteristics of PEM electrolyzer has been investigated. A detail discussion on the role played by charge transfer coefficient in influencing operating characteristics of PEM electrolyzer has been presented in this article. Experimental data was used to validate the accuracy of the finding of this research. Main interesting insights are that at CTC of 0.5 and 0.2 for anode and cathode respectively, the operating voltage at 1 A/cm2 (current density) is around 2.0 V, however at CTC of 2 and 0.5 for anode and cathode respectively, there was significant drop in operating voltage up to 1.62 V with current density of 1 A/cm2, this accounts for about 27% reduction in operating voltage. It was also discovered that with exchange current density of 1 × 10–7 for a Pt–Ir anode based electrode the CTC value for anode increase from 0.27 to 0.34 at current density of 0.05 A/cm2 to 2 A/cm2 respectively, whereas for Pt cathode catalyst with exchange current density of 1.8 × 10–3 the CTC values for cathode increased from 0.02 to 0.14 at current density of 0.1 A/cm2 to 2 A/cm2 respectively, these findings were in agreement with the CTC values reported in the literature. Image 1 • Irreversibilities in PEM electrolyzer is dominated by activation overpotential. • Thicker membrane has highest ohmic resistance. • CTC enhances the electro kinetic of the reaction at anode electrode. • PEM electrolyzer requires less power density at higher CTC. [ABSTRACT FROM AUTHOR]